Tap A can fill an empty tank in 5 mins. When tap A and B are turned on at the same time, they can fill the empty tank in 3 mins. How long does it take for Tap B to fill the empty tank?
( please help to solve this question and show your working clearly, thank you !! )

Tap A can fill an empty tank in 5 mins. When tap A and B are turned on at the same time, they can fill the empty tank in 3 mins. How long does it take for Tap B to fill the empty tank?
( please help to solve this question and show your working clearly, thank you !! )